Impact resistant laminated spin bobbin

ABSTRACT

A NEW AND IMPROVED SAFETY INNER TUBULAR LINER IS INCORPORATED INTO A COMPOSITE LAMINATED TUBULAR VOIDLESS BOBBIN. THE INNER TUBULAR LINEAR IS MADE UP OF LAYERS OF CRESYLIC ACID-PHENOL FORMALDEHYDE RESIN AND COTTON FABRIC IMPREGNATED WITH CRESTYLIC ACID PHENOL FORMALDEHYDE RESIN. THE INNER TUBULAR LINEAR IS FORMED BY RESIN IMPREGNATING A COTTON SHEET MATERIAL, COATING THE IMPREGNATED SHEET ON ONE SIDE WITH AN ADDITIONAL AMOUNT OF THE RESIN, ADVANCING TO THE B STAGE, PASSING THE SHEET, RESIN COATING FACE UP, OVER A HOT ROLL AND WINDING ONTO A HEATED MANDREL.

Jan. 5, 1971 CRAWFORD ETAL 3,553,046

IMPACT RESISTANT LAMINATED SPIN BOBBIN 2 Sheets-Sheet 1 Filed Jan. 2, 1968 l u I n r I1 Ill/Ila 6 Ill I" n 7 6 n u m n} 7 III IIIIlIIl-v 6 9 iffy/[ill 62 SC-RAPED SIDE Jan. 5, 1971 T. G. CRAWFORD ETAL 3,553,046

IMPACT RESISTANT LAMINATED SPIN BOBBIN Filed Jan. 2, 1968 2 Sheets-Sheet 73 FIG.|.

PAPER IMPREGNATED LAYERS I I I" INVENTORS Thomas G. Crawford and Wiiliom E. Keorse. %%4% ATTORNEY WITNESSES United States Patent 3,553,046 IMPACT RESISTANT LAMINATED SPIN BOBBIN Thomas G. Crawford, Hampton, and William E. Kearse,

Fairfax, S.C., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 2, 1968, Ser. No. 695,161 Int. Cl. B65h 81/02 U.S. Cl. 156--184 7 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to bobbins and to methods for manufacturing them. More particularly, this invention relates to composite laminated tubular members adapted for use as bobbin barrels in the manufacture of bobbins. 0

For many years, the synthetic textile yarn industry has used a steel bobbin or pirn for draw twisting nylon and similar synthetic yarns. Originally, a paper cover Was placed over the steel body to protect the yarn from contaminants and to prevent fiber discoloration. Recently, covers or sleeves of acrylonnitrile-butadiene-styrene resin overcame some of the difficulties encountered with the paper covered steel bobbin. The covers, however, have a relatively short life. Damaged or worn covers must be replaced or reconditioned and a substantial amount of labor is devoted solely to this work in the textile yarn plants.

Some of the foregoing problems were solved and other advantages were obtained by making bobbins or pirns with laminated paper phenolic tubular barrels, as for example, the pirn described and claimed in U.S. Pat. 2,879,010, assigned to the assignee of this invention.

One of the main difficulties with an all paper-phenolic bobbin has been its brittleness. This is especially dangerous when a bobbin has been dropped and a crack occurs. The crack starts from inside and works outward in a very high percentage of cases. In most cases the cracks are small and hard to detect. When the cracked bobbin is put on a winding collet and rotated at normal speeds the cracked bobbin will often fiy apart. The fragments may be sharp and could cause serious injury to persons in the area.

SUMMARY OF THE INVENTION Accordingly, it is the general object of this invention to provide a new and improved safety bobbin with a tubular barrel having a novel construction that is highly resistant to impact.

Another object of this invention is to provide new and improved methods of fabricating void free laminated tubular barrels in bobbins.

Briefly, the foregoing objects are accomplished by using resin coated impregnated fabric as the inner liner of the 3,553,046 Patented Jan. 5, 1971 BRIEF DESCRIPTION OF THE DRAWING For a better understanding of the nature and objects of the invention, reference may be had to the following drawings, in which:

FIG. 1 is a vertical cross section through a pirn or bobbin;

FIG. 2 is a cross section of one-half of a symmetrical bobbin barrel;

FIG. 3 shows a method of impregnating the paper sheet material used for the outer layers of the bobbin barrel;

FIG. 4 shows a method of impregnating and kiss coating the fabric sheet material used for the safety inner layers of the bobbin barrel; and

FIG. 5 shows a method of forming the bobbin barrel using a heated roll and mandrel.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention cresylic acid-phenol formaldehyde varnish is used to impregnate and coat fabric sheet material used as the inside layers of the tubular member that forms the body of a pirn or bobbin.

Referring now to FIG. 1 of the drawing, there is illustrated a cross section of a type bobbin 10, in accordance with this invention. The bobbin comprises a laminated outer tubular portion or barrel 11 composed of plural layers of paper impregnated With a solid cured infusible resin. The barrel 11 of the bobbin can be made, for example, by passing unbleached kraft paper having a thickness of six mils and a basis weight from 49 to 54 pounds (24 x 26"500 sheets) through a bath of epoxy modified phenol formaldehyde varnish and then through squeeze rolls to leave a resin solids content of to The impregnated paper may have a greenness of flow of 8 to 12% after the resin has been B-stage cured in an oven with temperatures varying from 2l0'to 270 F., the paper passing through the oven with a dwell time of about 2 to 10 minutes. Greenness is determined by the test described in U.S. Pat. 2,383,430. To secure a high strength bobbin barrel, the resinous impregnant must have from 2 to 6 parts of thermosettable epoxy resin per parts of phenolformaldehyde thermosettable, resin. Such an outer tubular barrel resists abrasion and scratching.

The varnish used to impregnate the paper has been made, for example, by blending about 4 parts of a liquid aromatic base epoxy resin having an epoxide equivalent weight of about 175-210 (for example Shell Chemical Company, Epon 828), about 0.3 part of a wetting agent (for example National Aluminate Company, Nalco 212), 100 parts of a phenol-formaldehyde composition described hereinbelow, together with sufficient methanol to give a liquid impregnating composition having a viscosity of about 3080 centipoise at 25 C. and a recoverable solids content of from 51 to 53% by weight.

The phenol formaldehyde composition is made by charging a vessel with 130 parts phenol, parts formaldehyde, and 0.35 part ammonia, by weight. The charge is refluxed for 90 minutes, the mixture being vacuum dehydrated at the end of this period to remove substantially all of the water. At the end point, the vent valve is opened and 82 parts methanol are added. The product is then cooled. A resinous composition is thus produced having a viscosity of 75-200 centipoise at 25 C. with a 3 recoverable solids content of 54-57% by 'Weight. The ingredients of the above compositions can vary il%.

FIG. 1 also shows the impact resistant inner bobbin liner 12 comprising from about 1 to 4 layers of impregnated coated fabric. The impact resistant inner safety liner is made by passing eight ounce unbleached cotton drill having a thickness of about 15 mils through a bath of the cresylic acid phenol-formaldehyde composition described below and then through squeeze rolls to leave a resin ratio of 2.05-2.15 and a greenness of flow of 25- 35% after the resin has been cured to its B-stage. The resin of the impregnated cotton drill is B-staged by passing the impregnated cotton drill through a 2-10 to 270 F. oven with a dwell time of about 2 to 10 minutes. This cotton fabric must receive a kiss coat or other one sided treatment of the above-mentioned cresylic acid phenol formaldehyde composition. A kiss coat is preferable to a complete dip and squeeze so as to get maximum thickness of the resin layer and yet not contaminate the heated roll during the tube rolling step described hereinafter. Other methods such as flow coating or spray coating could also be used.

The cresylic acid phenol-formaldehyde composition is made by charging a vessel with 130 parts cresylic acid, 15 parts phenol, 110 parts formaldehyde, 0.3 part of ethylene diamine and 1.5 parts ammonia, by weight. The charge is refluxed for 30 minutes, the mixture being vacuum dehydrated at the end of this period to remove substantially all of the water, until the reaction product is clear and dry to touch at room temperature. When that point is reached about 35 parts of methanol and about 35 parts of toluol, by weight, are added to provide a resinous composition having a viscosity Of 60 to 175 centipoise at 25 C. with a recoverable solids content of 57 to 59% by weight. The ingredients in the above composition can vary from +5 to FIG. 1 also shows a drive end bushing and an internal guide bushing 17. These end members are press fitted into the bobbin barrel and fit on the spindle on which the pirn is to be rotated. Such bushings are in accordance with the prior art and form no part of the invention herein.

FIG. 2 shows a cross section of one-half of a bobbin 10 with outer barrel 11 comprising paper impregnated layers, inner liner 12 comprising fabric, as for example, cotton, impregnated layers 25, 27, and coated resin layers 26, 28. Also shown is the seal lap 24 where the paper sheet edge is fitted under a small section of the fabric sheet on the mandrel to provide void free composite laminations throughout the bobbin barrel.

FIG. 3 illustrates the paper impregnating step described above. A roll of fiber sheet 30, such as kraft paper, passes into a varnish dip pan 32 beneath a roller 33 immersed in impregnating varnish 35, such as the heretofore described epoxy modified phenol formaldehyde varnish, so that the paper sheet is soaked in the impregnating varnish. The paper sheet then passes between a pair of squeeze rolls 34 where the amount of applied impregnating varnish is controlled by the setting of the rolls. The paper sheet is then preferably drawn over a scraper 36 to remove superficial varnish from that one side of the paper and finally passes into oven 37 where the solvent from the resinous varnish is evaporated. The solvent vapors escape through the stack 38. The product 39 coming from the oven comprises paper sheet impregnated with B stage resin and may be wound into a roll 40.

FIG. 4 illustrates the same impregnating steps as FIG. 3 except'here a fabric roll 60, such as cotton, polyethylene terephthalate, viscose rayon, or nylon, is used and is immersed in the heretofore described cresylic acidphenol formaldehyde varnish 65. After passing through oven 67 where the resin is cured to the Bstage the resin impregnated fabric is kiss coated to about a 1.50 mil wet film thickness by rollers 72 as shown with the cresylic acid-phenol formaldehyde varnish 71. This kiss coating is applied only to the top of the fabric. Again it moves through an oven 73 where the wet film coating is cured to the B-stage. The product 75 is then wound into a roll 76. The preferred .wet resin coating thickness is 1.0 to 3.0 mils thick. The kiss coating may through recycling be applied to a 5.0 mil wet film thickness without harming the strength of the bobbin barrel. The impregnated cotton fabric was fed face down into the rollers 72. The bottom roller applies a coating of the resin contained in dip pan 70.

The tubular members are made as shown in FIG. 5. First the impregnated, coated cotton fiber sheet described above is passed over hot roll 91 as shown heated to a temperature from to 175 C. at a speed of 50120 inches per minute, to soften the B-staged resin. The sheet then passes onto a lightly lubricated mandrel, 94, where two layers are wound. The fabric is then cut with a knife across the length of the mandrel. Then the impregnated paper sheet heretofore described in detail is passed over roll 91 under the same conditions as above. It then passes onto mandrel 94 where it is fitted under a small section of the impregnated cotton fabric, the seal lap, and is wound to form a plurality of void free layers until the desired bobbin barrel thickness, about 50 layers, is reached. The metal mandrel 94 is heated to a temperature of 100-120 C. During winding, pressure roll 93 exerts a uniform pressure of about 9 to 12 pounds per lineal inch along the length of the tube. Maximum web tension is maintained on the material during winding to assure a tight tube and a good bond. The other roll 92 is water cooled. After the tube is rolled to the desired wall size, it is baked for 2 to 4 hours at C. to fully cure the resin to a solid infusible thermoset stage. The final thickness of the rein coating is about A mil minimum and may reach about 1 mil when the maximum resin wet film thickness of 5 mils is used. That coating forms the innermost part of the bobbin barrel. The cotton fiber sheet passes over the hot roll 91 as shown so that the resin layer does not contact the heated roll. If the coating contacted the hot roll it would melt and contamimate the roll. This also permits the mandrel to pick up the kiss coated impregnated cotton sheet easily and so avoid wrinkles because the resin coating is soft after passing the heated roll and sticks easily to the mandrel. It is important to avoid wrinkles at this stage because they would produce a weak spot or void in the final product. The impregnated paper sheet is passed over the hot roll 91 so that the scraped side contacts the hot roll. The bobbin thus produced has a void free laminated barrel with a safety liner that is highly resistant to impact. Tests have shown that such bobbins have a longitudinal IZOD impact resistance of 0.65 foot pounds per inch of notch and circumferential IZOD impact resistance of 0.82 foot pounds per inch of notch. This is for the composite bobbin. The inner portion, cotton impregnated and coated portion, has a longitudinal IZOD impact resistance of 2.40 foot pounds per inch of notch and a circumferential IZOD impact resistance of 1.75 foot pounds per inch of notch. The bobbins quite often are hurriedly placed on their steel winding collets and the higher impact resistance of the safety cloth liner and its strategic location gives the bobbin a much longer life.

While there have been shown and described what are at present considered to be the preferred embodiments of this invention, modifications thereto will readily occur to those skilled in the art. It is not desired therefore that the invention be limited to the specific arrangements, embodiments and methods shown and described and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

We claim:

1. A composite laminated tubular voidless safety bobbin barrel comprising (1) an inner tubular linear of alternate layers comprising (a) plural layers of a fabric sheet material impregnated with a thermoset cresylic acid-phenol formaldehyde resin and (b) plural layers of thermoset cresylic acid-phenol formaldehyde resin having a thickness between A mil to 1 mil, said resin layers forming the inner most layer and layers between and bonding together said fabric sheet layers, (2) an outer tubular portion bonded to the inner liner comprising a plurality of layers of paper sheet material impregnated and bonded together by a thermoset epoxy modified phenol-formaldehyde resin having 2 to 6 parts by weight epoxy resin for each 100 parts of a phenol formaldehyde resin.

2. The composite laminated tubular voidless safety bobbin barrel of claim 1 wherein the fabric sheet material is selected from the :group consisting of cotton, nylon, polyethylene terephthalate and viscose rayon.

3. The composite laminated voidless safety bobbin barrel of claim 3 wherein the inner tubular liner comprises from about 1 to 4 layers of impregnated fabric sheet material and from about 1 to 4 layers of resin.

4. The composite laminated tubular voidless safety bobbin barrel of claim 2 wherein the impregnated paper sheet material has some superficial resin thereon.

5. A method of producing a composite laminated tubular voidless safety bobbin barrel comprising an inner tubular liner and an outer tubular portion, comprising the steps: (1) impregnating paper sheet material with a thermosettable epoxy modified phenol formaldehyde resin and heating the resin to a partially cured state; (2) impregnating a fabric sheet material with a cresylic acid-phenol formaldehyde resin, and heating the resin to a partially cured state; (3) coating said impregnated fabric sheet material on one side to a thickness between 1 and 5 mils with a layer of cresylic acid-phenol formaldehyde resin and heating said resin layer to a partially cured state to form a resin-fabric composite; (4) passing said resin-fabric composite over a hot roll, so that the resin-layer does not contact the hot roll, wrapping at least two turns of said composite onto a heated mandrel to form an inner tubular liner of alternate resin-fabric layers having a resin layer forming the innermost layer and layers between the fabric layers: (5) passing said impregnated paper sheet material over the hot roll and wrapping a plurality of turns onto the mandrel to form an outer tubular portion until the desired bobbin barrel thickness is reached; (6) heating the bobbin barrel to fully cure the resins to a solid fusible state.

6. The method of claim 5 wherein the epoxy modified phenol formaldehyde resin composition has 2 to 6 parts by weight of an epoxy resin for each 100 parts phenol formaldehyde resin.

7. The method of claim 5 wherein the fabric sheet material is selected from the group consisting of cotton, nylon, polyethylene terephthalate and viscose rayon.

References Cited UNITED STATES PATENTS 2,273,373 2/1942 Perry 242118.32 2,945,638 7/1960 Crawford et al. 242118.32 2,976,889 3/1961 Cannady 138-141 3,054,428 9/1962 Crawford 242118.32X 3,323,751 6/1967 Cunningham et al. 242-11832 3,350,030 10/1967 Green 242118.32 3,451,433 6/1969 Cunningham et al. 138-144 3,455,521 7/1969 Cunningham et al. 242118.32

CARL D. QUARFORT H, Primary Examiner G. SOLYST, Assistant Examiner US. Cl. X.R.

156l9l, 192; 242-l18.32 

